Stabilization of oils



Patented Apr. 23, 1940 UNITED STATES PATENT OFFICE Sidney Musher, New York, N. Y.,

Musher Foundation Incorporated,

assignor to New York,

N. Y., a corporation of New York No Drawing. Application December 20, 1939, Serial No. 310,149

'7 Claims. (Cl. 99-163) This invention relates to the stabilization of glyceride oils and particularly when used for edible purposes, the process to be described being acceptable for use for food oils and being relatively inexpensive and simple.

In accordance with my copending application, Serial No. 292,613, filed August 30, 1939, which continues the subject matter of my application, Serial No. 135,169 filed April .5, 1937, there is added to and dispersed in a glyceride oil a combination of a water soluble carbohydrate, particularly a sugar, and a phosphatide such as lecithin, and the combination of sugar and phosphatide after having been dispersed in the oil is heated with the oil to elevated temperature, desirably in excess of about 250 F. and preferably in excess of 400 F. whereby the glyceride oil is' substantially stabilized against oxidative deterioration.

In accordance with the instant invention, a

glyceride oil which contains not less than about i 0.1% of phosphatide such as lecithin, and preferably as much as 0.2%, is stabilized by having added to it a relatively small proportion, less than 3%, and desirably between 0.05% and 1% of a finely divided water soluble carbohydrate, prefer- -ably a mono-saccharide such as dextrose and desirably in dry or dehydrated condition and the oil containing the finely divided sugar thoroughly dispersed therein is then heated to an elevated temperature in excess of 250 F. and desirably in excess of 400 F. for a short period of time whereby the oil is substantially stabilized against oxidative deterioration.

In addition to containing not less than about 0.1% of vegetable phospatide, such as lecithin, dissolved in the oil and part of the oil, the glyceride oil should desirably contain not less than about 1% total unsaponifiable matter as apparently the combination of the lecithin and the unsaponifiable matter reacts with the added sugar at the elevated temperature in .order to produce a reaction product with the oil, thereby stabilizing the oil against deterioration.

The sugar which is added may be any one of the broad class of the water soluble carbohydrates including the mono-saccharides, di-saccharides, and poly-saccharides, but preferably a monosaccharlde or di-saccharide is employed such as dextrose, sucrose, fructose, mannose, arabinose or lactose. The crude or refined cane or beet sugars may be employed and preferably the crude sugars and there may also be utilized the residues obtained from the refining processes of such sugars such as molasses including blackstrap molasses, and sorghum molasses.

The most desirable results, however, are obtained from the use of the mono-saccharides. Particularly dextrose is employed for addition to the phosphatide containing oil which is then subjected to the elevated temperature.

As little as 011% of dextrose, for example, added to a phosphatide containing glyceride oil, such as to maize oil, and with the dextrose having been dispersed throughout the oil heated to a temperature in excess of about 250 F. will stabilize the oil.

Preferably, the sugar is actually burnt or charred in the oil as apparently theburning or charring process results in the proper reaction between the sugar and the oil containing the phosphatide whereby stabilization takes place.

Temperatures as high as from 400 F. to 500 F. are desirably employed and the heat treatment may continue for a period of from 5 to seconds up to minutes or more. The higher the temperature, the greater the stabilizing effect. This is quite surprising in view of the fact that it is normally to be expected that when oils are subjected to an elevated temperature, they become more readily subject to rancidity and less stable.

It is particularly desirable to use in accordance with this process the substantially unrefined, or crude oils which have not been subjected to any causticating treatment which would tend to remove some of the naturally occurring phosphatides remaining in the oil following the expressing or solvent extraction process. For example, the sugar such as dextrose maybe added to crude unrefined cottonseed oil, corn oil, sesame oil, olive oil (frequently referred to as virgin olive oil), wheat germ oil and oat oil, which oils are then heated to the elevated temperature to obtain the markedly enhanced stabilization.

' These oils may also be treated with sugar, however, and particularly with dextrose, following the causticating and other refining operations provided after such causticating and refining treatments, there remains in the oil not refinery molasses less than about 0.1% and preferably 0.2% of phosphatide such as lecithin.

Such oils as cccoanut oil, palm kernel oil or lard (as made from chopped hog fat) do not satisfactorily react with dextrose when subjected to the elevated temperature inasmuch as they do not appear to contain the necessary 0.1% of lecithin, but such oils as rice .germ oil, maize germ oil, oat germ oil, or cottonseed oil, for example, which contain a sufllcient' quantity of phosphatide, such as lecithin, will react with the dextrose under the conditions of the elevated gredient for reaction with the lecithin or phosphatide contained in the oil and the added dextrose at the elevated temperature of treatment.

Where the oil with or without causticating or bleaching or Winterizing to remove excess stearine, is heated to an elevated temperature of between 350 F. and 450 F. with superheated steam being blown through the oil at the elevated temperature, the sugar such as dextrose may be added to the oil before being subjected to the elevated temperature oftreatment. Preferably thedextrose is added to the oil immediately following the blowing of the superheated steam through the oil while the oil'is at the maximum temperature of treatment, as at between 350 F. and 450 F., so that the dextrose remains dispersed in the oil at that temperature for a period of about 5 or 10 minutes or more. For example, following the blowing of the superheated steam through the oil at a temperature of, for example, 410 F., the dextrose may be added to the oil and kept dispersed in the oil while the oil is dropped into the cooling tank. During the time required for cooling to room temperature, the sugar reacts with the oil at the elevated temperature in order to produce the desired stabilization.

Furthermore, even where the cooling tanks are not equipped with high vacuum apparatus so that the cooling of the oil is conducted under low vacuum or under an atmosphere of inert gas, the sugar added to the oil prior to the cooling operation reduces very materially the deterioration of the oil which would occur much more rapidly as a result of the cooling taking place under lower vacuum or at atmospheric pressure. For example, where only 20 inches of vacuum s employed while cooling an oil from 410 F. to room temperature, the presence of 1% of dextrose in the oil during the cooling results in an oil of much superiorstability to where a similar oil is cooled under 28 inches of vacuum and without the use of the dextrose.

In addition, where, during the superheated steam treatment of the oil for the period of from 3 hours to 8 hours, such process is conducted at lower vacuums, such as between 20 inches and 27 inches of vacuum, the presence of the dextrose is important to prevent loss of stability.

The fish and fish liver oils suchas cod liver -oil, halibut liver oil, herring oil and menhaden oil appear to contain sufficient phosphatides to react satisfactorily with the sugar at the elevated temperature. However, those animal fats which are rendered from chopped hog fat or chopped beef fat in the production of ordinary lard and tallow do not appear to contain sufficient phosphatide to react with sugar at the elevated temperature.

In the case of lard which is rendered from chopped hog fat, in order to obtain a hog lard which will react with the sugar, it is desirable toadd to the rendering kettle a sufilcient quantity of hog brains or cartilage or nerve tissue in order to bring up the phosphatide content to the desired minimum of 0.1% and the lard which is then rendered will contain the phosphatide so that such lard will react with the sugar at the elevated temperature and preferably when the sugar is actually burnt in the lard.

. In addition to the presence of lecithin or phosphatide in the oil, there may also be reacted with the sugar other substances including phythin,

phytic acid, and phosphoric acid which may be carried into the oil at the time of the expressing.

procedure. It is, of course, possible to add either lecithin or phosphoric acid to the oil in order to increase the total lecithin or phosphoric acid content in the oil in order to bring up the total' amount of lecithin which is required for reaction the most desirable reaction to take place with the oil.

In addition to using the sugars referred to, there may also be employed the sugar phosphates or other carbohydrate phosphates, the di-, tri-, tetraand hexa-phosphates being generally satisfactory. These are made by combining the carbohydrates in stoichemical proportions with phosphorus pentoxide or phosphorus oxychloride with or without the addition of catalytic and dehydrating agents such as, for example, zinc chloride or aluminum chloride followed by heating up to about 100 C. preferably under a vacuum of about 15 inches. These compounds are preferably added to an oil which has been freed of water and if necessary the oil may be dehydrated first.

The carbohydrate or sugar sulfates or-mixed sulfates and phosphates may also be used. Less preferably there can be used the tartrates and citrates of sugar and other similar carbohydrates.

Where the glyceride oils contain over about 2% of 'unsaponifiable matter and particularly where the oils have not been causticized or bleached some stabilization may be obtained by merely heating the oil to an elevated temperature in excess of about 250 F. and preferably to about 400 F. without the addition of the sugar such as dextrose.

The crude and unrefined fish and fish liver oils, such as cod liver oil, halibut liver oil and herring oil, may particularly be improved in keeping quality by heating to over about 250 F. and preferably to 300 F. to 400 F. for a short period of time such as forfrom 2 to 15 minutes. heating process, it is undesirable to pass superheated steam through the oil and preferably the oil is heated under vacuum or atmosphere of inert gas.

Apparently, in addition to the phosphatide present, certain amine compounds are also present in sufiicient quantity to react with the phosphatide in a similar manner to the dextrose reacting with the phosphatide where the dextrose is added to the oil. Although it is considered preferable for thedextrose to be added to the During this either aliphatic chains or aromatic or alicyclic rings which in certain instances are effective even in the absence of phosphatides and where the heating in the oil is above about 250 F. to

The sugar or other carbohydrate which is charred or burnt in the oil at from 250 F. to 500 F. may be filtered from the oil following the elevated temperature treatment. Where a portion of the unsaponifiable matter may be removed by filtration, as in the case of corn oil, such filtration should desirably take place following the elevated temperature treatment of the sugar in the oil and after the stabilization has occurred.

Although it is desirableto have at least 0.1% of phosphatide present in the oil before addition of the sugar followed by heating to charring tern peratures, nevertheless, with certain types of oils which are particularly subject to oxidative deterioration ithas been found that some improvement is obtained with even smaller quantities of phosphatide present, such as 0.025% to 0.05%.

This application is acontinuation in part of applications, Serial No. 292,613, filed August 30, 1939, Serial No. 269,913, filed April 25, 1939, and Serial No, 260,898, flied March 10, 1939, and is related in subject matter to application, Serial" No. 315,487, filed January 25, 1940. Through said prior filed applications, the present application also continues the subject matter of my application, Serial No. 135,169, filed April 5, 1937.

Having described my invention, what I claim is:

1. A process of stabilizing glyceride oils containing in excess of about 0.1%

, and then heating to over 250 F.,

glyceridebils are substantially stabilized against taining in excess of about 0.1% total phosphatide which comprisesv adding and dispersing therein a small 'ainount, less than 3%, then heating to over of dextrose and 250 F., whereby said glyceride oils are substantially stabilized against oxidative deterioration.

2. A process of stabilizing glyceride oils contotal phosphatide which comprises adding and dispersing therein a small amount of a monosaccharide sugar and then heating to over 250 F., whereby said glyceride oils are substantially stabilized against oxidative deterioration.

3. A process of stabilizing phosphatide containing glyceride oils which comprises adding and dispersing-therein a small amount of a sugar whereby said oxidative deterioration.

4. A process of stabilizing vegetable liquid glyceride oils containing phosphatides which comprises adding and dispersing therein a small.-

amount of ,a finely divided sugar and then heating to a charring temperature or over 350 F., whereby v said glyceride oils are substantially stabilized against oxidative deterioration.

5. A process of stabilizing phosphatide containing cottonseed dispersing therein a small amount of a sugar and then heating to over 250 F., whereby said cottonseed oil is substantially stabilized against oxidative deterioration.

'6. A process of stabilizing phosphatide containing corn oil which comprises adding and dispersing therein a small amount of a sugar and then heating to over 250 F., whereby said corn oil is substantially stabilized against oxidative deterioration.

.7. A process of stabilizing phosphatide containing corn oil which comprises adding and dispersing therein a small amount oil which comprises adding and oidextrooeand then heating to a charring temperature of over 350 1"., whereby said corn oil is substantially stabilized against oxidative deterioration.

sinus! 

